One of the main arguments that Christians often throw against the prophet Muhammad is his treatment of the Banu Qurayza tribe, they allege that what happened to the Jewish tribe was a crime, and something abhorrent, which proves that Muhammad (AS) couldn't be a true prophet.

In this article I shall discuss the incident in its full and proper context, by doing this we shall all see that the prophet Muhammad did not commit any crime, and that the Christians as usual have twisted the story, and not only have the Christians twisted the story, they have also shown their double standards.

So with that said let us proceed to the evidences, we go right to the start, when the prophet Muhammad entered the city of Medina. Now the city of Medina had a large Jewish population, so it was necessary for the Muslims to form some sort of agreement with the Jewish tribes, this would keep the law and order between the two groups, so the prophet Muhammad made a covenant with the Jewish tribes, a sort of constitution you could say. The covenant stated the following as we see from Ibn Ishaque's Sirat Rasul Allah:

This is a document from Muhammad the prophet between the believers and Muslims of Quraysh and Yahtrib, and those who followed them and joined and laboured with them. They are one community to the exclusion of all men. The Quraysh emigrants according to their present custom shall pay the bloodwit within their number and shall redeem their prisoners with the kindness and justice common among believers. The B. Auf according to their present custom shall pay the bloodwit they paid in heathenism; every section shall redeem its prisoners with the kindness and justice common among believers. The B. Saida the B. ?l-Harith, and the B. Jusham, and the B. al-Najjar likewise. The B. ?Amr b. Auf, the B. al-Nabit and the B. al-Aus likewise. Believers shall not leave anyone destitute among them by not paying his redemption money or bloodwit in kindness.

A believer shall not take as an ally the freedman of another Muslim against him. The God-fearing believers shall be against the rebellious or him who seeks to spread injustice, or sin or enmity, or corruption between believers; the hand of every man shall be against him even if he be a son of one of them. A believer shall not slay a believer for the sake of an unbeliever, nor shall he ain an unbeliever against a believer. God's protection is one, the least of them may give protection to a stranger on their behalf. Believers are friends one to the other to exclusion of outsiders. To the Jew who follows us belong help and equality. He shall not be wronged nor shall his enemies be aided. The peace of the believers is indivisible.

No Separate peace shall be made when believers are fighting in the way of God. Conditions must be fair and equitable to all. In every foray a rider must take another behind him. The believers must avenge the blood of one another shed in the way of God. The God-fearing believers enjoy the best and most upright guidance. No polytheist shall take the property or person of Quraysh under his protection unless the next of kin is satisfied (with blood money), and the believers shall be against him as one man, and they are bound to take actions against him. It is not lawful to a believer who holds by what is in this document and believes in God and the last day to help an evil-doer or to shelter him. The curse of God and his anger on the day of resurrection will be upon him if he does, and neither repentance nor ransom will be received from him. Whenever you differ about a matter it must be referred to God and to Muhammad.

The Jews shall contribute to the cost of war so long as they are fighting alongside the believers. The Jews of the B. Auf are one community with the believers (The Jews have their religion and the Muslims have theirs), their freedmen and their persons except those who behave unjustly and sinfully, for they hurt but themselves and their families. The same applies to the Jews of the B. al-Najjar, B. al-Harith, B. Saida, B. Jisham, B. al-Aus, B. Tha'laba, and the Jafnam a clan of Tha'laba and the B. al-Shutayba. Loyalty is protection against treachery. The freedman of Tha'laba are as themselves. The close friends of the Jews are as themselves. None of them shall go out to war save the permission of Muhammad, but he shall not be prevented from taking revenge for a wound. He who slays a man without a warning slays himself and his household, unless it be one who has wrong him, for God will accept that. The Jews must bear their expenses and the Muslims their expenses. Each must help the other against anyone who attacks the people of this document. They must seek mutual advice and consultation, and loyalty is a protection against treachery.

A man is not liable for his ally's misdeeds. The wronged must be helped. The Jews must pay with the believers so long as war lasts. Yathrib shall be a sanctuary for the people of this document. A stranger under protection shall be as his host doing no harm and committing no crime. A woman shall only be given protection with the consent of her family. If any dispute or controversy likely to cause trouble should arise it must be referred to God and to Muhammad the apostle of God. God accepts what is nearest to piety and goodness in this document. Quraysh and their helpers shall not be given protection. The contracting parties are bound to help one another against any attack on Yathrib. If they are called to make peace and maintain it they must do so; and if they make a similar demand on the Muslims it must be carried out except in the case of a holy way. Every one shall have his portion from the side to which he belongs, the Jews of al-Aus, their freedmen and themselves have the same standing with the people of this document in pure loyalty from the people of this document.

Loyalty is a protection against treachery: He who acquires aught acquires it for himself. God approves of this document. This deed will not protect the unjust and the sinner. The man who goes forth to fight and the man who stays at home in the city is safe unless he has been unjust and sinned. God is the protector of the good and the God-fearing man and Muhammad is the apostle of God. (Alfred, Guillaume. The Life of Muhammad, A Translation of Ibn Ishaq's Sirat Rasu Allah. Oxford University press, 2002. PP. 231-232)

So as you can see this treaty laid out specific rulings, that the Muslims and the Jews would be allies to one another, and wouldn't aid an enemy against the other, and it even went further to specifically state that anyone who took the Qurayshi pagans as allies would suffer the consequences. With these clear rulings in place, let us now go the battle of the trench, the battle of the trench was basically a Qurayshi pagan offensive against the city Medina, the pagans were seeking to destroy the Muslim community once and for all, the events that took place during this incident are recorded by Ibn Ishaque, we read the following:

A number of Jews who had formed a party against the apostle...went to Quraysh at Mecca and invited them to join them in an attack on the apostle so that they might get rid of them altogether. Quraysh said, ?You, O Jews, are the first scripture people and know the nature of our dispute with Muhammad. Is our religion the best or his? They replied that certainly their religion was better than his and they had a better claim to be in the right...These words rejoiced the Quraysh and they responded gladly to their invitation to fight the aposle, and they assembled and made their preparations. Then the company of Jews went off to Ghatafan of Qays Aylan and invited them to fight the apostle and told them that they would act with them and that Quraysh had followed their lead in the matter; so they too joined in them. Quraysh marched under the leadership of Abu Sufyan...When the apostle heard of their intention he drew a trench about Medina and worked at it himself encouraging the Muslims with hope of reward in heaven. The Muslims worked very hard with him...When the apostle had finished the trench, Quraysh came and encamped where the torrent-beds of Ruma meet between al-Juruf and Zughaba with ten thousand of their black mercenaries and their followers from Najd and halted at Dhanab Naqma towards the direction of Uhud. The apostle and the Muslims came out with three thousand men having Sal' at their backs. He pitched his camp there with the trench between him and his foes, and have orders that the women and children were to be taken up into the forts. ( Ibid., pp. 450, 452-453)

Some points must be made, as you can see the Quraysh marched against Medina on the instigation of some Jewish leaders, the prophet eventually found out and dug a trench. Now the prophet Muhammad and the Muslims dug the trench at the north of Medina, the other parts of Medina were covered by tree fields and rocky hills, hence the prophet and the Muslims didn't need to dig trenches around Medina as a whole, but only from the North which was the main opening. Now at the south of Medina were the tribe of Banu Qurayza, who had made an agreement with the prophet Muhammad and the Muslims, these factors should all be kept in mind. Let us continue with the incident:

The enemy of God Huyayy b. Akhtab al-Nadri went out to Ka'b b. Asad al-Qurazi who had made a treaty with the apostle. When Ka'b heard of Huyayy's coming he shut the door of his fort in his face, and when he asked permission to enter he refused to see him, saying that he was a man of ill omen and that he himself was in a treaty with Muhammad and did not intend to go back on his word because he had always found him loyal and faithful. Then Huyayy accused him of shutting him out because he was unwilling to let him eat his corn. This so enraged him that he opened his door. He said, Good heavens, Ka'b, I have brought you immortal fame and a great army. I have come with Quraysh with their leaders and chiefs which I have halted where the torrent-beds of Ruma meet; and Ghatafan with their leaders and chiefs which I have halted in Dhanab Naqma towards Uhud. They have made a firm agreement and promised me that they will not depart until we have made an end of Muhammad and his men. Ka'b said: By God, you have brought me immortal shame and an empty cloud which had shed its water while it thunders and lightens with nothing in it. Woe to you Huyayy leave me as I am, for I have always found him loyal and faithful. Huyayy kept on wheedling Ka'b until at last he gave way in giving him a solemn promise that if Quraysh and Ghatafan returned without having killed Muhammad he would enter his fort with him and await his fate. Thus Ka'b broke his promise and cut loose from the bond that was betweenhim and the apostle.

When the apostle and the Muslims heard of this he apostle sent Sa'd b. Mu'adh b. al-Nu'man who was chief of Aus at the time, and Sa'd b. Ubada b. Dulaym...They went forth and found the situation even more deplorable than they had heard; they spoke disparagingly of the apostle, saying, who is the apostle of God? We have no agreement or undertaking with Muhammad. (Ibid,. pp. 453)

So as you can see, the Banu Qurayza tribe broke the treaty between themselves and the Muslims, they decided to join the Qurayshi pagan onslaught, so the Muslims were now effectively surrounded from the north by the pagans, and the south by the Jewish tribe of Qurayza. So now the battle was all about wait and see, it was like a game of chess, the pagans were finding it very hard to launch a full offensive because of the trench, and the Jewish tribe would not attack on their own, they were waiting for the Qurayshi pagans to go full in, once the Qurayshi pagans went with their full force, the Jewish tribe of Qurayza would attack the Muslims from the south, this tactic would be an attempt to over-whelm the Muslims.

The prophet Muhammad knew the situation was very bad, so he had to act quick, and he came up with a plan to send a Muslim to infiltrate within the ranks of the Qurayza and the pagan army to cause distrust between the two:

Then Nu'aym b. Mas'ud b. Amir b. Unayf b. Tha'alaba b. Qunfud b. Hilal b. Kalawa b. Ashja b. Rayth b. Ghatafan came to the apostle saying that he had become a Muslim though his own people did not know of it, and let him give what orders he would. The apostle said: you are only one man among us, so go and awake distrust among the enemy to draw them off us if you can, for war is deceit. Thereupon Nu'aym went off to B. Quryaza with whom he had been a boon companion in heathen days, and reminded them of his affection for them and of the special tie between them. When they admitted that they did not suspect him he said: Quraysh and Ghatafan are not like you; the land is your land, your property, your wives, and your children are in it; you cannot leave it and go somewhere else. Now Quraysh and Ghatafan have come to fight Muhammad and his companions and you have aided against him, but their land, their property, and their wives are not here, so they are not like you. If they see an opportunity they will make the most of it; but if things go badly they will go back to their own land and leave you to face the man in your country and you will not be able to do so if you are left alone. So do not fight along with these people until you take hostages from their chiefs who will remain in your hands as security that they will fight Muhmmad with you until you make an end of him. The Jews said that this was excellent advice.

Then he went to Quraysh and said to Abu Sufyan b. Harb and his company: You know my affection for you and that I have left Muhammad. Now I have heard something which I think it my duty to tell you of by way of warning, but regard it as confidential. When they said that they would, he continued: Mark my words, the Jews have regretted their action in opposing Muhammad and have sent to tell him so, saying: Would you like us to get hold of some chiefs of the two tribes of Quraysh and Ghatafan and hand them over to you so that you can cut their heads off? Then we can join you in exterminating the rest of them. He has sent word back to accept their offer; so if the Jews send to you to demand hostages, don't send them a single man.

Then he went to Ghatafan and said: You are my stock and my family, the dearest of men to me, and I do not think that you can suspect me. They agreed that he was above suspicion and so he told the same story as he had told Quraysh. On the night of the Sabbath of Shawwal A.H. 5 it came about by God's action on behalf of his apostle that Abu Sufyan and the chiefs of Ghatafan sent Ikrima b. Abu Jahl to B. Qurayza with some of their number saying that they had no permanent camp, that the horses and camels were dying; therefore they must make ready for battle and make an end of Muhammad once and for all. They replied that it was the Sabbath, a day on which did nothing, and it was well known what had happened to those of their people who had violated the Sabbath. Moreover we will not fight Muhammad along with you until you give us hostages whom we can hold as security until we make an end of Muhammad; for we fear that if the battle goes against you and you suffer heavily you will withdraw at once to you country and leave us whole the man is in our country, and we cannot face him alone. When the messengers returned with their reply Quraysh and Ghatafan said that what Nu'aym told you is the truth; so send to B. Qurayza that we will not give them a single man, and if they want to fight let them come out and fight. Having received this message B. Quryaza said: What Nu'aym told you is the truth. The people are bent on fighting and if they get an opportunity they will take advantage of it; but if they do not they will withdraw to their own country and leave us to face this man here. So send word to them that we will not fight Muhammad with them until they give us hostages. Quraysh and Ghatafan refused to do so, and God sowed distrust between them, and sent a bitter cold wind against them in the winter nights which upset their cooking-pots and overthrew their tents.

Then Abu Sufyan said: O Quraysh, we are not in a permanent camp; the horses and camels are dying; the B. Qurayza have broken their word to us and we have heard disquieting reports of them. You can see the violence of the wind which leaves us neither cooking-pots, nor fire, nor tents to count on. Be off, for I am going! Then he went to his camel which was hobbled, mounted it, and beat it so that it got up on its three legs...When Ghatafan heard of what Quraysh had done they broke up and returned to their own country. In the morning the apostle and the Muslims left the trench and returned to Medina, laying their arms aside. (Ibid,. pp 458-460)

So one Muslim managed to sow distrust between the Pagan Quraysh and the Jewish Quryaza, compounded with the bad weather conditions, the Pagans decided to retreat, and hence the Muslims came out victorious. So let us summarize what we have so far:

-The Muslims were in a treaty with the Banu Qurayza

-The Pagans launched an offensive against the Muslims

-The Banu Qurayza broke the treaty and joined the pagan offensive

-The Banu Qurayza were simply waiting for the pagans to launch their complete offensive against the Muslims so they too could launch their offensive against the Muslims fromthe south

-The Banu Qurayza had every intention of killing the prophet Muhammad and the entire Muslim community

So with all of that said, the Banu Quryaza are far from innocent, off course the Christians don't bother to mention any of this, in fact the Christians probably support the pagan offensive as well as the Jewish betrayal! Perhaps the reasons Christians use this argument is because they are so angry that the enemies of God failed in their assault, and the Muslims survived, and this is why the Christians are so angry about this case.

Let us now continue with the incident, the battle has now ended, but Banu Qurayza's punishment is yet to come, we continue to read:

The prophet ordered it to be announced that none should perform the afternoon prayer until after he reached B. Qurayza. The apostle sent Ali forward with his banner and the men hastened to it. Ali advanced until he came near the forts he heard insulting language used of the apostle. (Ibid., pp.461)

So notice even after their treacherous act, the Jewish tribe are still asking for a fight, Ali went to their fort and they started insulting the prophet Muhammad, they do this instead of asking for forgiveness and apologising for their crime.

Now so far we have seen that the Quryaza tribe broke the treaty, and on top of that they aren't repentant and persist in their crimes, so therefore it is without a doubt that they do deserve a punishment, now this is one of the main arguments that is thrown on this case, which is that the Qurazya tribe were killed in a brutal fashion, well let us read about how this punishment came about:

In the Morning they submitted to the apostles judgement and al-Aus leapt up and said, O apostle, they are our allies, not allies of Khazraj, and you know how you recently treated the allies of our brethren. Now the apostle had besieged B. Qaynuqa who were allies of al-Khazraj and when they submitted to his judgement Abdullah B. Ubayy b. Salul had asked him for them and he gave them to him; so when al-Aus spoke thus the apostle said: Will you be satisfied, o Aus, if one of your own number pronounces judgement on them? When they agreed he said that Sa'd b. Mu'adh was the man...Sa'd said, Then I give judgement that the men should be killed, the property divide, and the women and children taken as captives. (Ibid,. pp. 464)

So the prophet allowed Sa'd to judge over the Banu Qurayza tribe, and the prophet did this at a request of the Aus tribe who were allies with the Qurayza tribe, furthermore Sa'd himself was a former Jew. Now Christians claim that this ruling is so wrong and barbaric, but here is the icing on the cake, Sa'd a former Jew judged these Jews by THEIR OWN LAW! Here is the law from the Jewish Bible:

When thou comest nigh unto a city to fight against it, then proclaim peace unto it. And it shall be, if it make thee answer of peace, and open unto thee, then it shall be, that all the people that is found therein shall be tributaries unto thee, and they shall serve thee. And if it will make no peace with thee, but will make war against thee, then thou shalt besiege it: And when the LORD thy God hath delivered it into thine hands, thou shalt smite every male thereof with the edge of the sword: But the women, and the little ones, and the cattle, and all that is in the city, even all the spoil thereof, shalt thou take unto thyself; and thou shalt eat the spoil of thine enemies, which the LORD thy God hath given thee. (Deuteronomy 20:10-14)

So notice the double standards and hypocrisy of these Christians, they are attacking the prophet Muhammad for what happened to the Jews of Banu Qurayza, yet when this is in their own Bible they have no problem with it! The Jewish tribe of Qurayza were judged by their own book, their own law, and if Christians feel this is something detestable then they should go burn their Bible and rip this ruling out of their book.

So let us summarize everything we have:

-The prophet Muhammad was in a treaty with the Qurayza tribe

-The Qurayza tribe broke the treaty

-Once they broke the treaty they were liable for a punishment

-The Qurayza are not innocent

-The prophet Muhammad made Sa'd the leader who would pronounce judgement over the Quryaza tribe

-The prophet did this at the request of the Al-Aus tribe, an ally of Qurayza

-Sa'd a former Jew judged the Banu Qurayza by their own Torah, from Deuteronomy 20

So when you put all of this together, we see that no crime was committed, and that the Qurayza tribe are far from innocent, and that the prophet Muhammad didn't kill them just for the sake of being Jewish, or because he was supposedly evil.

So in conclusion I would advise the critics of Islam to be more sincere and honest in their arguments.